Beginning in the early '90s with CamelBak, the hydration pack market has boomed. Early on we mountain bikers discovered that we could more easily pack our gear, and sufficient water for far away excursion in these slimmed down backpacks. Since then, hydration packs have come in all shapes and sizes. From small waist pack types to humongous day packs that will hold enough for an overnight stay in the forest... and your water. And tools. And camera. And... just about anything you can think of, really. Ergon is fairly new to this crowded market. They have made a name for themselves making grips that are very ergonomic, and they have carried this tight focus on how the body interacts with their gear to the BD-1.

The main premise behind the BD-1 is that the weight of the pack and contents should be carried by the wearers hips. Anyone who has backpacked knows this and most internal and external frame packs are designed with this in mind. The should straps should be used to stabilize the load. Most hydration packs don't behave this way. In fact they are the opposite. They carry the weight on the wearers shoulders and use the waist belt as a stabilizing belt. Taking a page from external packs, the BD-1 has a stiff outer frame that transfers the load to the hips, as designed. There was one big hurdle that Ergon had to overcome in order to make a pack this rigid. They had to allow the riders upper body to move, yet keep the pack stationary. Let's face it, mountain biking takes a bit of body english, and the last thing you'd want is a pack that curtailed this motion. The solution that Ergon came up with is the Flink ball joint. The main part of the pack is on one side of the Flink, while the shoulder harness is on the other. This allows the shoulder harness to rotate in all directions around this point, essentially decoupling the shoulder harness from the stabilizing frame. The shoulder harness is also adjustable vertically to accomodate different sized riders. I used it in the lowest position, but another tester used the same pack in the highest position. We both had a good fit.

The shoulder harness isn't the only thing that is a fresh design. Most waist straps merely cinch the pack to your body, not the waist belt on the BD-1. Since it is attached to the frame on the sides, it can be tightened from the front and the back, essentially holding the pack away from your body, while making the belt as tight as you'd like it. It's a nice touch. The pack is really full of nice touches, though. Like the integrated rain cover, or velco loops on the shoulder straps to hold hydration hose, or the rear gear webbing. The BD-1 has been well thought out.

In use, the external frame takes some getting used to. The pack isn't the lightest around, but it carries its weight well. I did find that it would generally take me about half a mile to get it situated... to get comfortable with it. Once I had it on right, I forgot about all the technical details and just rode, unhampered by the pack. Really, the pack only made itself known to me on two occasions: when I was standing up, cranking out of the saddle and when I went to take a drink. Since the pack sits off your back by a bit, swinging your torso side to side swings the pack more. This isn't to say that it bounces, it doesn't. It just feels like the weight is out there. Also, again because the pack sits away from the wearer, you'll want to use a bladder with the longest hose you can find. All of the ones I used were too short and I really had to turn my head far to get a drink. Ergon will be selling their own bladder--the BD-1 doesn't come with a bladder--with an extra long hose, but it isn't available as of this writing.

I did find that the size of the pack is just about ideal. It's big enough for an all day ride--it'll fit a jacket, food, tools and the like easily--but it's not so big that on shorter rides you feel like you are using the wrong pack. At 12 liters of cargo space, it's a good compromise. If that's not enough, Ergon has the BD-2 with 15 liters of capacity and will soon have the BD-3 available with a whopping 30 liters of capacity. As for me, I'll stick with the BD-1. I carry too much stuff anyway.

Summary: Ergon has created a pack that stands apart in the crowded hydration pack market. By applying their knowledge of ergonomics, they've created an innovative pack that manages to separate upper body motion from lower, while staying stable. The Flink joint is brilliant, and it's this--along with the external frame--that makes the BD-1 unique. All of this innovation comes at a price, and at $150 the BD-1 is not cheap, particularly since it doesn't come with a bladder. That being said, this is a well made piece of equipment that will handle the abuse that comes with riding off road. If you are in the market for a new hydration pack, you really need to try the Ergon BD-1. You might not look at hydration packs the same again.

James Sharp is a contributing editor for GearReview.com; more of his ramblings and a look at upcoming reviews can be found at his blog -- Lactic Acid Threshold.